This invention relates to needleless fluid transfer and, more particularly, to valves and other connectors for introducing and removing fluids with respect to a patient.
When entry is needed into the vascular system of a patient, an intravenous tubing set is commonly used with a primary needle or catheter that accesses the vascular system, and a connector valve is coupled to the needle through tubing for repeated use of a medication delivery system, including a syringe. With such a tubing set, the trauma to the patient is reduced to a single puncture of the vascular system by the primary needle.
Repeated use of the syringe for introducing fluids into the Valve connector does not result in additional patient trauma. In some cases, the connector forms an injection site, an adapter, or extension set for medication added to a constant flow of intravenous solutions through the connector. The intravenous solution flows from an elevated container through the connector into the primary needle or catheter, and medications are typically added to the intravenous solution at the connector.
The valve connectors generally include a sealed entry port which communicates through the tubing and the primary needle into the vascular system of the patient. This sealed entry port is typically constructed of a latex plug sometimes referred to as a septum. Medication is introduced into the connector by penetrating the septum with the secondary needle. The latex septum is self-sealing such that the needle hole created in the septum automatically closes when the secondary needle is removed.
A major drawback of conventional practice is associated with the use of a secondary needle to puncture the septum. Once a needle is exposed to the body fluids of a patient, within a short distance from the insertion site, the injection is considered high risk, and the contaminated needle threatens the health care workers with disease and other life-threatening injuries.
Several devices have been developed which provide for secondary access without the use of the secondary needle. Representative of these devices in the apparatus disclosed in U.S. Pat. No. 5,242,432 issued to DeFrank which discloses a safety valve for introducing medication into a patient. Although such devices may eliminate the risk of secondary needle stick, they present other risks which relate to the pooling of fluid on or around external surfaces. ideally, a connector or other access device should not promote pooling during the ordinary course of its use due to potential for bacterial infection. If a reservoir or cavity is created and not cleaned, bacteria may develop in the reservoir. That bacteria could find its way into the patient""s bloodstream while either administering fluids to the patient or removing the fluids from the patient.
In U.S. Pat. No. 5,782,816 which issued to Werschmidt et al. on Jul. 21, 1998 for Bi-directional Valve and Method, the disposable needleless access device is adaptable for use in various medical procedures. Although this device can eliminate the need for a secondary needle, it has a housing with an axis extending between a proximal end and a distal end, with a valve element in the housing movable to form a curved axis by insertion of a male Luer fitting into the proximal end of the housing.
Injection sites used with a blunt cannula have the advantage that the cannula will not pierce the skin of a user, but the preslit injection site has to reseal with enough force that fluids do not ooze outwardly and not allow airborne particulate matter, bacterial or viral, to enter.
Hence, there continues to be a need for an injection site which can be used with a variety of solutions and over a range of fluid pressures. Further, there continues to be a need for such an injection site which will reliably reseal even after many insertions of a blunt cannula.
If intended to be reusable, the injection site should be able to receive a large number of insertions of the cannula without displaying reseal failure. Such an injection site should provide for alignment of the cannula on insertion to result in less chance of damage to the injection site after repeated insertion.
Further, the injection site should be usable with a blunt cannula with a reasonable level of insertion force that will permit health care personnel to readily insert the cannula, but yet not have the cannula easily displaced after insertion.
Accordingly it is an object of the invention to achieve the foregoing advantages without the need for a displaceable plug that adopts axis curvature in order to permit fluid flow.
In accomplishing the foregoing and related objects, the invention provides a needleless valve connector formed by a housing having an axis extending between a proximal end and a distal end, with a fixed elastomeric support at the proximal end and containing a valve seat against which is disposed a valve element or plug within the housing. The valve element is movable away from the valve seat by a fitting inserted into the proximal end of the housing.
In accordance with one aspect of the invention a side housing communicates with the housing axis beyond the position of maximum movement of the valve element or plug.
The housing and the fixed elastomeric support have a wipable surface at the proximal end, and the valve element has a wipable surface at the proximal end when it is disposed in the housing against the valve seat.
The valve element has a symmetrical axis which is maintained when a force is directed thereagainst, and the valve element can cant or tilt from its initial position to a final position when a force is directed thereagainst.
The valve element has an axis aligned with that of the housing and the elastomeric support when the valve element is positioned against the valve seat, but the axis of the valve element forms an acute angle with the axis of the housing when the valve element or plug is depressed.
In accordance with another aspect of the the invention the proximal end of the housing overlaps the proximal end of the stretchable elastomeric support, and the support is longitudinally grooved to receive longitudinal ribs or flutings of the plug to provide flow channels between the plug and the interior wall of the housing.
In a method of the invention for operating a needless valve the steps include: (a) engaging a plug positioned against an elastomeric support at a proximal end of a housing; and (b) depressing the plug against the support away from a valve seat therein while extending the elastomeric support.
The method includes disposing the plug in the housing against the valve seat; and moving the plug away from the valve seat by insertion of a fitting into the proximal end of the housing, which has a wipable surface at its proximal end. The valve element or plug also has a wipable surface when it is disposed in the housing against the valve seat, so that the entire proximal end of the valve connector is wipable by disinfectant before use in order to assure the elimination of pathogens.
The valve element has a symmetrical axis which is maintained when a force is directed against the valve element, and the proximal end of the housing overlaps the proximal ends of the support.
In a method of the invention for manufacturing a needless valve the steps include: (a) positioning an elastomeric support member at a proximal end of housing; and (b) positioning a plug against a seat in the support. The support is longitudinally slotted, and the plug is longitudinally ribbed, with the ribs forming flutings. The distal end of the housing can include an interior inclined ramp therein.